Operating mechanism



Jan. 8, 1946.

A. R. SANBORN OPERATING ME'cHANIsM Filed Aug. l4`, 1944 lnQetor: Arthur R. S amborn Patented Jan. 8, 1946 2,392,700 OPERATING MECHANISM Arthur R. Sanborn, East Orange, N. J., assignor to General Electric Company, a corporation of New York Application August 14, 1944, Serial No. 549,397

' (c1. 'i4- 112)v 4 Claims.

My invention relates to operating mechanism, more particularly to snap action operating mechanism for drum or cam switches of the rotating type, and has for its object a simple, inexpensive and reliable snap operating mechanism.

In carrying out my invention in one form, I provide a stationary latching ring, together with a. driven member connected to the switch, which driven member is provided with two pawls cooperating with the latching ring for each direction of rotation. I also provide an operating member normally positioned by a snap spring in a predetermined angular relation with the driven member and provided with a cam for releasing one of the pawls when the driving member is turned to provide for movement of the driven member by the snap spring.

For a more complete understanding of my invention, reference should be had to the accompanying drawing, Fig. 1 of which is a side elevation view of operating mechanism embodying my invention; Fig. 2 is a view similar to Fig. l but showing parts in section; Fig. 3 is a plan view of the mechanism shown in Fig. 1 with the cover removed; Fig. 4 is a view similar to Fig. 3 but with the operating member removed; Fig. 5 is a view similar to Fig. 3 but showing the operating member displaced for movement of the switch to the next position; while Fig. 6 is a view similar to Fig. 5 but with the operating member removed.

Referring to the drawing, I have shown my invention in one form as applied to the snap stepby-step operation of a shaft I which is connected to operate a drum or cam type switch 2. The shaft I extends through a bore in a stationary supporting plate 3 which may be secured to a supporting structure as by lugs (not shown) formed on it. Mounted rigidly on the plate 3 in concentric relation with the shaft I is a latching ring 4 provided on its periphery with a plurality of equally spaced projections or lugs 5 with which cooperate pawls 6 and 1 carried by a positioning member 8 secured to the upper end of the shaft I. By means of the pawls 6 and 1. the positioning member 8 and the shaft I are held against rotation respectively in clockwise and counterclockwise directions. By means of an operating or driving member 9 pivoted on the axis of the shaft I, one or the other of the pawls can be moved `out of engagement with the latching ring for movement of the positioning member 8 and the shaft from one projection to the next on the latching ring.

This step-by-step movement of the positioning member 8 is effected by means of a helical snap spring I0 of the compression type mounted between the ends of two arms II and I2 which are pivotally mounted about the axis of the shaft I. As shown in Fig. 2, the positioning member 8 is provided with an upwardly extending hub I3 on which the arms II and I2 are pivoted. The snap spring I0 forces the ends of the arms II and I2 apart normally against upwardly extending projections I4 and I5 on the positioning member 8, these projections having a height somewhat less than one-half the width in a vertical direction of the ends of the arms I I and I2, against which the spring I0 bears.

On the lower side of the operating member 8 are two projections I6 and I1 which are spaced apart the same distance as the projections I4 and I5 and which embrace the ends of the arms II and I2. Thus, the operating member 9 is held by the arms II and I2, as normally biased by the snap spring I0, in a predetermined angular rela-f tion with the positioning member 8, as shown in.

Figs. 3 and. 4.

To effect the release of one or the other of the pawls upon angular movement of the operatingv member, the operating member is provided on its movable end with a straight cam face or surface I8 which normally is positioned, as shown in Fig. 3, at right angles with that radius of the latching ring 4 extending midway between the adjacent. ends of the pawls 8 and 1. This cam face I8 is in. position to engage one or the other of rollers I9.v and 20 mounted on arms 2I and 22, which arms are secured to upright shafts 23 and 24 on the lower ends of which the pawls are secured.

Thus, in the operation of the device, when the operating member 9 is turned, as by a shaft 25 rigidly secured to it, in a counterclockwise direction, as shown in Figs. 5 and 6, the cam face I8 engages the roller I9 thereby to move the pawl 6 clockwise against the force applied by its biasing spring 26 out of engagement with the latching ring 4. Figs. 5 and 6 show, as indicated in Fig. 6. the position of the parts just prior to complete disengagement of the pawl 6 with the latching ring. This movement of the operating member 9 moves with it the arm I I by engagement of the projection I6 with the arm, as indicated clearly in Fig. 6, whereby the snap spring I0 is compressed. Thusfwhen the pawly 6 is moved out of engagement with the projection on the latching ring, the positioning member 8 and the shaft I are snapped quickly by the spring I0 in a counterclockwise direction to the next position with the pawl 6 in engagement with the next projection on the latching ring, the pawl 1 sliding over its next projection. It will be observed that this corresponding movement of the positioning member 8 brings it again into correspondence with the operating member 9 and the pawl is then moved counterclockwise by its biasing spring 26 into engagement with the latching ring.

Another feature of my invention is a resilient mounting for the pawls 6 and 1 to provide for cushioning of the shock when the positioning member 8 and the shaft I are snapped to the next position. As shown in Fig. 4, the pawl 1 is mounted pivotally on the end of an arm 21 whose other end is secured to the positioning member 8 by means of a pivot 28. The arm 21 is biased normally against the side of the member 8 by means of a helical spring 29 mounted en a rod` 30 which extends loosely through a hole in the arm 21 and is secured to the member 8. A similar mounting arm 3| and biasing spring 32 are provided for the pawl 6, this arm 3| being connected to the member 8 by a pivot 33. It will be understood that when the pawl 6 or 1 engages the next notch, the spring 32 or 30, as the case may be, yields to cushion the shock.

As shown in Figs. 1 and 2, the operating mechanism is enclosed by a cover 34 which rests on the plate 3 and which is provided with a central bore for the shaft 25. The lower end of the shaft is further secured by extending into a bore in the hub I3 on the member 8.

While I have shown and described particular embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein wtihout departing from the invention and, therefore, it is aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. Operating mechanism for electric apparatus comprising an arcuate latching member provided with spaced latching projections, a driven shaft, a positioning member secured to said shaft, an operating member provided with a cam, spring means for biasing said positioning member and said operating member in a predetermined angular relation with respect to each other, latching: means on said positioning member arranged to cooperate with said latching projections to secure said positioning member against turning movement in each direction, spring means for biasing said latching means into engagement with said projections, and releasing means for moving each of said latching means out of engagement with said projections, said releasing means being arranged to be engaged by said cam when said cperating member is turned thereby to move said latching means to release said positioning member for rotation in the direction of movement of said operating member whereupon said positioning member and said shaft are snapped by said rst spring means to their next position.

2. Operating mechanism for electric apparatus comprising a stationary latching ring provided with spaced peripheral latching projections, a driven shaft concentric with said ring, a positioning member secured to said shaft, an operating member movable about the axis of said shaft provided with a cam face, spring means for biassaid positioning member and said operating member in a predetermined angular relation with respect to each other, two pawls pivotally mounted on said positioning member arranged to cooperate with said latching projections to secure said positioning member respectively against turning movement in each direction, springs for biasing said pawls into engagement with said projections, releasing means for moving each of said pawls out of engagement with said projections, said releasing means being arranged to be engaged selectively by said cam surface when said operating member is turned thereby to move the one of said pawls securing said positioning member against rotation in the direction of movement of said operating member whereupon said positioning member and said shaft are snapped by said spring means to their next position.

3. Operating mechanism for electric apparatus comprising a stationary latching ring provided with spaced peripheral latching projections, a driven shaft concentric with said ring, a positioning member secured to said shaft, spaced projections on said positioning member, two arms pivotally mounted on said shaft having end portions between said projections, a helical snap spring between said arms biasing them against said projections, said arms extending above said projections, an operating member pivoted on the axis of said driven shaft provided with a substantially straight cam face and with a. pair o! projections embracing said arms whereby said spring normally holds said operating member in a predetermined angular relation with said positioning member, two pawls pivotally mounted on said positioning member on opposite sides thereof, said pawls extending toward each other into engagement with said latching ring, springs for biasing said pawls into engagement with the projections on said latching ring, and means for moving each of said pawls out of engagement with said latching ring selectively engaged by said cam face when said operating member is turned thereby to release the one of said pawls securing said positioning member against rotation in the direction of movement of said operating member whereupon said positioning member and said driven shaft are snapped by said snap spring to their next position.

4. Operating mechanism for electric apparatus comprising a stationary latching ring provided with spaced peripheral latching projections, a driven shaft concentric with said ring, a positioning member secured to said shaft, spaced projections on said positioning member, two arms pivotally mounted on said shaft having end portions between said projections, a helical snap spring between said arms biasing them against said projections, said arms extending above said projections, an operating member pivoted on the axis of said driven shaft provided withk a substantially straight cam face and with a pair of projections embracing said arms whereby said spring normally holds said operating member in a predetermined angular relation with said positioning member, two pawl arms pivotally mounted on said positioning member on opposite sides iereof, a pawl on the end of each of said pawl arms, said pawls extending toward each other into engagement with said latching ring, springs for biasing said pawls into engagement with the projections on said latching ring, shock springs biasing said pawl arms against said positioning member, anv operating arm secured to each of said pawls normally held by said springs in position to be engaged by said cam face when said operating member is turned thereby to release the one of said pawls securing said operating member against rotation in the direction of movement of said operating member whereupon said positioning member and said driven shaft are snapped by said snap spring to their next position.

ARTHUR R. SANBORN. 

